Electrical relay



April 17, 1951 F. T. FEREDAY, SR 2,549,371

ELECTRICAL RELAY Filed Jan. 5, 1949 LLl/l l/ll/ Insulation JNVENTOR.

H15 ATTORNEY Patented Apr. 17, 1951 ELECTRICAL RELAY Frederick T. Fereday, Sr., Louisville, Ky., assignor to The Union Switch and Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application January 5, 1949, Serial No. 69,251

/ 7 Claims.

My invention relates to electrical relays, and particularly to relays of the flasher type which may be used, for example, for controlling railway signals, or for controlling signals at an intersection of a railway with a highway, to display a flashing indication.

In order to adjust the time characteristics of a flasher relay for effecting the flashing of each signal light at a rate within suitable limits, it is customary to provide the core of the flasher relay with a plurality of short-circuited windings such, for example, as copper washers. One form of flasher relay is provided with two control windings which are repeatedly energized alternately for effecting the flashing of the signal lights. The copper washers delay the decay of magnetic flux in each control winding when it becomes deenergized, and also delay the building up of magnetic flux in each control winding when it becomes energized. Therefore, the speed of operation of a flasher relay can be adjusted during manufacture by increasing or decreasing the number of copper washers.

It has been found, however, that after a relay speed of operation may vary from its initial speed. It is therefore desirable that some additional means be provided for adjusting the speed of operation of a flasher relay without having to disassemble the relay to add or remove copper washers after the relay has been in service.

One feature of my invention is the provision of a novel and improved relay structure in which the rate of operation of a relay can be readily adjusted without having to add or remove copper washers after the relay has been assembled.

I shall describe one form of electrical relay embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a side elevational view of a relay provided with one form of means embodying my invention for adjusting the speed of operation of the relay; Fig.

2 is a side elevational View similar to Fig. 1 except that portions of the relay are shown in section; and Fig. 3 is a diagrammatic view showing magnetic and electrical operating circuits for the relay shown in Figs. 1 and 2.

Similar reference characters refer to similar parts in each of the views.

Referring first to Figs. 1 and 2 of the drawings, a flasher relay, designated generally by the reference character A, is provided with a core 4 which consists of a bar of ferromagnetic material such, for example, as silicon steel having a low" silicon content.

A first hollow pole piece I of ferromagnetic material, closed at one end, is attached, by a screw 5 extending through its closed end, over one end of core 4, and a second hollow pole piece 2, which is similar to pole piece I, is attached, by a screw 6, over the opposite end of core 4. A portion Ia of pole piece I extends beyond the open end of pole piece I, and a similar portion 2a of pole piece 2 extends beyond the open end of pole piece 2 opposite to, but spaced from, the portion Id of pole piece I.

A third pole piece 3 is mounted on an intermediate portion of core 4.

Adjacent to, and on each side of, pole piece 3, core A is surrounded by a plurality of shortcircuited windings shown as copper washers I.

A first control winding 8 surrounds core 4 between pole piece I and washers I, and a second control winding 9 surrounds core 4 between pole piece 2 and washers I.

A disc I!) of ferromagnetic material, having an integral screw portion Ina, is supported above, and spaced from, portions Ia and 2a of pole pieces I and 2, respectively. Screw portion I0 1 of disc IE is rotatable in a locking nut II which is fixedly mounted in a brass support member l2. By rotation of screw portion Illa, disc I0 is therefore movable toward or away from portions to and 2a of pole pieces I and 2, respectively.

An armature I3 of ferromagnetic material is pivotally supported at I4 intermediate its ends and adjacent to third pole piece 3. End I3a of armature I3 is therefore movable toward pole piece I in response to energization of control winding 8, and end I3b of armature I3 is movable toward pole piece 2 in response to energizationof control winding 9. Armature I3 is provided with armature pins I5 and I6 of some suitable material such, for example, as brass, to prevent contact between armature I3 and the pole pieces I and 2, respectively. Plates I! and I8 of suitable electrical insulating material are attached to armature I3 for operating electrical contacts.

In order to compensate for variations in ambient temperature, armature i3 is supported at I4 by a strip I9 of material which has a low temperature ooefiicient of expansion. Strip I9 is in turn supported by a bracket 23 of material such as brass, one end of which is fixedly attached to pole piece I, and the other end of which is fixedly attached to pole piece 2.

During manufacture, a given speed of operation of the relay or other electromagnetic device is provided by mounting a suitable number of copper'washers "I on core 4 while disc It is retained in a given normal spaced relation to pole pieces I and 2, and while armature I3 is retained in a given normal spaced relation to pole piece 3.

After manufacture of the relay has been complete-d, and particularly after it has been in service for a time, further adjustment of its speed of operation may become desirable. Such further adjustment can be made readily by movement of disc IS toward or away from the pole pieces I and 2.

It follows that, with applicants invention, it is not necessary to disassemble the relay to adjust its rate of operation by adding or removing washers 7.

In Fig. 3, electrical circuits are shown for energizing control windings 8 and 9 of relay A. A contact 2 having front and back points, may be operated by armature 13 in such manner that it is normally open at its front and back points while windings 8 and 9 are unenergized, and becomes closed at its front point when winding 9 becomes energized, and becomes closed at its back point when control winding 8 becomes energized. To provide for such operation of contact 2!, armature 13 may be biased by some suitable means, such for example as contact spring 2!, to a position in which end lBb is nearer to pole piece 2 than end We is to pole piece I while windings 8 and 9 are unenergized.

Energization of relay A may be effected in any suitable manner such, for example, as by the closing of a manually operable contact V for supplying current from a suitable source, such as a battery Q, to the control windings of relay A. When contact V becomes closed while contact 21 is open at its front and back points, as shown in the drawing, a circuit is completed for energizing windings 8 and 5 in series, this circuit passing from battery Q, through rontat V, and windings 8 and 9, back to battery Q.

In response to energization of winding magnetic flux passes through a magnetic circuit including core pole piece 2, armature 3, an pole piece This magnetic circuit is she diagrammatically by a dot and dash line designated by the reference character aa. In response to energiration of winding magnetic flux also passes through a second magnetic cir c-uit, designated by the reference character cc. which is similar to magnetic circuit On account of armature i3 being biased to a position in which its end l-Sb is nearer to pole piece than its end its is to pole piece l, end 313 of armature l3 will now be attracted further toward pole piece 2 until stopped by armature pin i5. At the same time, in response to encrgizatier of winding 9, magnetic flux passes through a rd magnetic circuit uhich includes core 4, pole piece air gap beJween disc i2 and pole piece 2, disc iii, gap between disc l5 and pole piece i, and then through pole piece 5 back to core 4.

On account of end 63?) of armature !3 being moved toward pole piece 2 until stopped by pin it, contact 3! becomes closed at its frontpoint. Winding 9 is therefore shunted by contact 2% closed at its front point, and control winding 3 becomes energized by a circuit passing from battery Q, through contact f, winding and front point of contact 2 i, back to battery Q.

In response to energization of winding 8, magetic flux passes through magnetic circuit c-c. Also, in response to energization of wind- 8, magnetic flux passes through the magnetic circuit b-b, previously described, but in the opposite direction In response to the flux passing through magnetic circuit cc, end I3a of armature I3 is attracted toward pole piece I, thereby opening contact 2| at its front point and closing contact 2! at its back point. Winding 8 is therefore shunted by contact 2| at its back point, and winding 9 becomes energized by a circuit passing from battery Q, through contact V, back point of contact 2!, and winding 9, back to battery Q. End l3b is then again attracted toward pole piece 2, so that contact 21 opens at its back point and is again closed at its front point. The cycle of operations just described is then successively repeated as long as contact V remains closed.

If it is desired to adjust relay A to operate at a lower rate, disc H) is moved toward pole pieces I and 2 by rotating screw portion ma, thereby reducing the distance the magnetic flux passes in air between pole piece 2 and disc l0 and between disc l0 and pole piece I. The reluctance of magnetic circuit bb is thereby reduced, so that more flux will pass through circuit bb, and less will pass in circuit aa or c--c. If it is desired to adjust the relay to operate at a higher rate, disc IE] will be moved away from pole pieces I and 2, thereby increasing the distance in air which the fiux in magnetic circuit bb travels.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. An electrical relay comprising, a core member having a first end and a second end, a first pole piece in contact with said first end, a second pole piece in contact with said second end, a third pole piece in contact with said core at an intermediate location between said ends of said core, a first winding around said core between said first end and said third pole piece, a second winding around said core between said second end and said third pole piece, short-circuited winding means around said core member between said first end and said intermediate location and also between said second end and said intermediate location, a ferromagnetic shunt member movable toward or away from said first and second pole pieces for decreasing or increasing respectively the reluctance of a magnetic circuit path which includes said core and said first and second pole pieces and also said shunt member, and a ferromagnetic armature pivotally supported intermediate its ends adjacent said third pole piece for movement of one of its ends toward said first pole piece or movement of its opposite end toward said second pole piece in response to energization of said first or said second winding respectively.

2. An electrical relay comprising, a core having a first end and a second end, a first pole piece adjacent said first end, a second pole piece adjacent said second end, a third pole piece adjacent an intermediate portion of said core, a first winding around said core between said first end and said intermediate portion, a second winding around said core between said second end and said intermediate portion, short-circuited winding means around said core between said first end and said intermediate portion and also between said second end and said intermediate portion, a ferromagnetic shunt member movable toward or away from said first and second pole pieces for decreasing or increasing respectively the reluctance of a magnetic circuit path which includes said core and said first and second pole pieces and also said shunt member, and an armature pivotally supported adjacent said third pole piece for movement of one of its ends toward said first pole piece or movement of its oppositeend toward said second pole piece in response to energization of said first or said second winding respectively.

3. In combination, an electromagnet provided with a core consisting of a bar of ferromagnetic material mounted between a first and a second pole piece of ferromagnetic material, a third pole piece mounted adjacent an intermediate portion of said bar, a first control winding around said bar between said first and third pole pieces, a second control winding around said bar between said second and third pole pieces, short-circuited winding means around said bar between said first pole piece and said intermediate portion and also between said second pole piece and said intermediate portion, a disc of ferromagnetic material suspended by an integral screw portion from a fixed support for movement toward or away from said first and second pole pieces for varying the reluctance of a magnetic circuit portion between said first and second pole pieces, and an armature pivotally supported adjacent said third pole piece for movement of one of its ends toward said first pole piece or movement of its opposite end toward said second pole piece in response to energization of said first or said second control winding ,respectively.

4. In combination, an electromagnet provided with a core between a first and a second pole piece, a third pole piece adjacent an intermediate portion of said core, a first control winding around said core between said first and third pole pieces, a second control winding around said core between said second and third pole pieces, an armature located for movement in response to magnetic flux in said core produced by energization of each of said control windings, short-circuited winding means around said bar between said first pole piece and said intermediate portion and also between said second pole piece and said intermediate portion, and adjustable magnetic shunt means in multiple with the portion of said armature between said first and third pole pieces in a first magnetic circuit which includes said first and third pole pieces and also in multiple with the portion of said armature between said second and third pole pieces in a second magnetic circuit which includes said second and third pole pieces.

. ward said second pole piece in response to energization of said first or said second control winding respectively, short-circuited winding means around said bar between said first pole piece and said intermediate portion and also between said second pole piece and said intermediate portion, and variable magnetic shunt means in multiple with said armature in a first magnetic circuit path which includes said first and third pole pieces in series with each other and in a second magnetic circuit path which includes said second and third pole pieces in series with each other.

6. An electromagnetic device comprising, a core consisting of a magnetizable bar mounted between a first and a second pole piece, a third pole piece mounted adjacent an intermediate portion of said bar, a first control winding around said bar between said first and third pole pieces, a second control winding around said bar between said second and third pole pieces, shortcircuited winding means around said bar between said first and third pole pieces, other shortcircuited winding means around said bar between said second and third pole pieces, an armature placed with one of its ends adjacent said first pole piece and with its opposite end adjacent said second pole piece and with an intermediate portion of said armature adjacent said third pole piece, adjustable magnetic shunt means across said first and second pole pieces, a first magnetic circuit supplied by said first control winding with magnetic flux passing in a given direction through said bar between said first and third pole pieces and including a portion of said armature between said first and third pole pieces, a second magnetic circuit supplied by said second control winding with magnetic fiux passing in the opposite direction through said bar between said second and third pole pieces and including a portion of said armature between said second and third pole pieces, and a third magnetic circuit supplied at times by said first control winding with mag netic fiux passing in said given direction and supplied at other times by said second control winding with magnetic flux passing in said opposite direction through said bar between said first and second pole pieces and including said magnetic shunt means.

7. An electromagnetic device comprising, a magnetizable bar, an armature placed with one of its ends adjacent one end of said bar and with its opposite end adjacent the opposite end of said bar and with an intermediate portion of said armature adjacent an intermediate portion of said bar, a first control winding around said bar between said one end and said intermediate portion, a second control winding around said bar between said opposite end and said intermediate portion, short-circuited winding means around said bar between said one end and said intermediate portion, other short-circuited winding means around said bar between said opposite end and said intermediate portion, and adjustable magnetic shunt means across said ends of said bar on the opposite side of said bar from said armature.

FREDERICK T. FEREDAY, SR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

